Rayleigh信道空间相关及其对空时码性能的影响

Spatial Correlation in Rayleigh Channels and Its Effect on the Performance of Space-Time Codes

为了研究空间相关对空时编码性能的影响。假设散射量沿波达角的功率分布服从von Mises分布。推导出了Rayleigh衰落信道多径接收信号的角度扩展．引入近似的高斯函数型阵列空间互相关系数。构造接收等距线阵的空间相关矩阵。并证明该矩阵是正定和满秩的。其行列式取值介于0～1之间．分析表明：若空时码字的差异矩阵满秩且仅在接收端存在空间相关，只会造成空时编码传输在编码增益上的损失。而不会造成分集增益上的损失；Rayleigh空间衰落相关信道中的最优空时编码设计准则与Rayleigh空间衰落独立信道中的相同．

In order to study the effect of spatial correlation on the performance of space-tlme codes, an angular spread of multipath signals received in Rayleigh fading channels is presented with the assumption that the power distribution versus the angle of arrival （AOA） of scatter components follows the von Mises distribution. An approximative spatial correlation coefficient with a form of Gaussian function is introduced, a spatial correlation matrix for the reception uniform linear array is constructed. It is proved that the matrix is positive definite and full rank, and the determinant value of the matrix is between 0 ～ 1. A performance loss of space-time codes transmission is not in diversity gain but in coding gain only, if the space-time codeword difference matrices are full rank and in presence of the spatial correlation at the receiving end only. The design criteria for optimal space-time codes over correlated Rayleigh channels are the same as that over uncorrelated Rayleigh channels.